Electric, automatically reversing switches are known from for example German Patent Publication Nos. 2636632 and 3338452 and from U.S. Pat. No. 3,688,062 and 3,408,463, and although none of these publications seems to disclose switches intended for use in miniature electronic devices. The automatically reversing effect is imparted to the thus known automatically reversing switches either by a resilient force produced by constructing the end terminals as spring elements with which the lower end of the push rod is brought into contact when moved from its neutral position, or by use of a particular additional spring mechanism mounted in the upper part of the switch box, see for example U.S. Pat. Nos. 3,688,062 and 3,408,463. This is especially the case in the switch according to U.S. Pat. No. 3,408,463, which discloses a double-pole, double-throw electric switch for the reversing operation of a permanent magnetic motor and where the size of and clearance required by the springs or spring mechanisms in the switch box makes the switching mechanism as a whole relatively complex and space consuming, and a minimization, if any, for use in electronic miniature devices would thus encounter major problems when faced with the requirement to provide a simple and safely operating mechanism of very small outer dimensions the size of which should be comprised within about 3-4 min.
A hitherto use volume control in hearing aids is known from Danish Patent Publication No. 134876 wherein in a rotating potentiometer of very small outer dimensions is provided by a particular construction comprising a circular potentiometer resistance sheet divided into material sections having mutually different specific resistance and across which sections a sliding contact may be conductively connecting that portion of the sheet which corresponds to a desired volume control. Despite this minimized construction the rotating potentiometer in question and the accessory adjusting button are too large for incorporating into another unit, for example, the amplifier unit of a hearing aid, and consequently it should be included as a separate unit which contributes undesirably to an increase in the outer dimensions of the hearing aid aggregate.